Method and apparatus for regenerating the dialyzing fluid for an artificial kidney

ABSTRACT

THE METHOD AND APPARATUS FOR REMOVING THE WASTE METABOLITES FROM THE DIALYZING FLUID OF AN ARTIFICIAL KIDNEY WHEREIN THE TEMPERATURE OF THE DIALYZING FLUID IS LOWERED PRIOR TO THE FLUID ENTERING A FIRST CARBON SORBENT CHAMBER, THE CARBON ABSORBING THE WASTE METABOLITES, A PORTION OF THE FLUID LEAVING THE FIRST CHAMBER BEING RAISED IN TEMPERATURE AND MOVED INTO A SECOND CARBON SORBENT CHAMBER HAVING A HIGH PERCENTAGE OF ABSORBED WASTE METABOLITES, THE FLUID AFTER LEAVING THE SECOND SORBENT CHAMBER BEING LOWERED IN TEMPERATURE AND CAUSED TO COME INTO CONTACT WITH A THIRD SORBENT CHAMBER, A PORTION OF THE FLUID AFTER LEAVING THE THIRD SORBENT CHAMBER BEING RETURNED TO REENTER THE FIRST SORBENT CHAMBER.

f United Sra-tss Paseos @mee 3,697,418 Patented Oct. I0, 1972 3,697 41sMETHOD AND APPARATS BOR REGENERATING ABSTRACT F THE DISCLOSURE Themethod and apparatus for removing the waste metabolites from thedialyzng fluid of an articial kidney wherein the temperature of thedialyzing tluid is lowered 'prior to the iluid entering a tirst carbonsorbent chamber, the carbon absorbing the waste metabolites. a portionof the iiuid leaving the tlrst chamber being raised in temperature andmoved into a second carbon sorbent chamber having a high percentage ofadsorbed waste meta bolites, the duid after leaving the second sorbentchamber being lowered in temperature and caused to come into contactwith a third sorbent chamber, a portion of the fluid after leaving thethird sorbent chamber being returned to reenter the first sorbentchamber.

BACKGROUND OF THE INVENTION The tield of this invention relates toartilcial kidneys aud more particularly to a method and apparatus for regeneration of the dialyzing iiuid employed within an artificial kidneywhich is used to remove waste metabolities from animal blood.

A simble fraction of the people who die each year of kidney failure arefree from other complications and might be restored to a fairly normallife if their kidney function could be provided artificially. Atpresent. the artilicial kidney has been developed sumciently to permitlong-term sustenance ot' [ite by periodic hemodialysis.

Basically, the artificial kidney is composed of a large, thin membranewhich separates the blood from the dialyzing tluid. Normally, thedialyzng duid is u solution similar in ionic composition to blood andmade approximately isotonic by adding glucose. The blood may be,maintained at a higher pressure than the dialyzing duid, and water fromthe blood may be forced through the Amembrane by the pressuredifference. Waste metabolites,

such as urea, creatinine, and uric acid, are removed from the blood byditusing through the membrane in response to the existing concentrationgradients. Suicient removal ot the metabolic waste requires aconcentration dtference across the membrane to be held as high aspossible for each molecule to be removed. Hence, concenn'ation of thesematerials in the dialyzing tluid must be held low.

The problem of maintaining a low metabolic waste concentraton in thedialyziug iluid has been traditionally appreached in two ways. The tirstway is to discard the dialyzing uid after going through the artificialkidney. 'Ihe second way is to regenerate the dialyn'ng duid afterleaving the artificial kidney with the regenerated dlalyzing uid beingagain recycled through the kidney.

The normal person requiring the use of an artificial kidney must betreated several times a week. Normally, such treatments may take as longas ten hours at a time with between 50 and 100 gallons of dialyzing Huidbeing passed through the artificial kidney. Although the dialyzing fluidcan be made relatively inexpensively, because of the large volume of thetluid employed in each treatment and the frequency of treatments, thecost becomes substantial if the lluid is discarded after a single use.Further, effort is recently being made toward the designing of a smallcompact artificial kidney unit which can be em played withinthe home.The large volume of dialyng'tluldthatwouldbenecessaryifsuchwerediscardedafter a single pass throughthe kidney would preclude the use of such a compact unit. Clearly, theonly reasonable approach is to effect a regeneration of the dlalyzingtluid. Progress can be made in reducing the size of the articial kidneyif the dialyzing tluid volume can be reduced without loss of masstransfer eilciency.

Itlsknowninthepast that certaininertsolidsareuw ful in removing thewaste metabolites from the dialyzing iluid, the removal beingaccomplished by adsorption. This permits a recycle of a substantialamount of the dialyzing tluid without significant loss of mass transfereticiency. It

is diticult to select a suitable inert solid which has a high capacityfor the waste metabolites. Activated carbon has a sufficiently highcapacity for uric acid and creatinine, two waste metabolites which mustbe removed. However. inconveniently large amounts of activated carbonare required to remove urea which must be removed in substantialquantity.

The adsorption of urea by activated carbon is reversible, indicatingthat periodic regeneration can give an effective increase in capacity.Activated carbon adsorbs urea to an extent depending upon temperature.In other words, the lower the temperature, the greater the level ofmaximum adsorption characteristic, and the higher the temperature, thelower the adsorption characteristics of the carbon.

SUMMARY OF THE INVENTION The method and apparatus of this inventionrelates to the extraction of waste metabolites, and primarily urea, fromthe dialyzing duid ot an artificial kidney. The dialyzing iluid, afterremoval from the artificial kidney, enters a rst sorbent chamber at alowered temperature. The tirst sorbent chamber then etects substantialremoval of the urea from the dialyzing iluid. After the lluid leaves thetrst sorbent chamber, the lluid is divided with approximately onethirdof the iluid volume being conducted imo a second sorbent chamber. Thetluid entering the second sorbent chamber is signitieantly raised intemperature. The activated carbon located in the second sorbent chamberis to have previously adsorbed a maximum or near maximum amount of ureaat a much lower temperature. As a result, the urea located within thesecond sorbent chamber is transmitted from the activated carbon backinto the dialyzing llnid passing through the second chamber, thusregenerating the carbon of the second chamber. A valve system is locatedbetween the first and second sorbent chambers to etect switching of suchwhen the ilrst sorbent chamber has adsorbed maximum or near maximumamount of urea and when the second sorbent chamber has given olf themaximum amount or near maximum amount of urea. The primary portion ofthe dialyzing liuid leaving the first sorbent chamber is then conductedback to the inlet side of the artificial kidney. The portion of thedialym'ng iluid leaving the second sorbent chamber is then significantlylowered in temperature and transmitted through a third sorbent chamberwhich effects removal of a substantial portion of the contained urea.The dalyzing duid leaving the third sorbent chamber is divided with themaior portion of the duid being transmitted back to reenter the rstsorbent chamber. It is to be noted that the concentration of urealeaving the third sorbent chamber should be approximately equal to orbelow the urea concentration of the uid from the artificial kidney. 'Ihedivided portion of the fluid from the third sorbent chamber is elevatedin temperature and passed through a fourth sorbent chamber. Again, thefourth sorbent chamber is to com tain activated carbon which haspreviously adsorbed a V near maximum amount of urea. 'I'he activatedcarbonis to the portionof the-dillyzin uid thclethrough'withthatAuvidlbeing then of exterior of thesystem. ve'arrangement is.assoeiaeedbhetween the' third and fourth sorbentchambers so its toatleet a-switching of such for regeneration of the gus-th. chamber endmaximum adsorption ot the. third amber..`

BRIEF DESCRIPTION F DRAWING FIG. l is asehematicbiock diagram of the(dialyzing fluid)` dialysste regenerationsystem of this invention; and

FIG. 2 is achart depicting temperature dependence ofurcaadsorptionofatypicalactivatedcarhonfora particular 4urea solutionconcentration.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT' Referring in PIG. l aconventional artlcial kidney 1li-iu schematic form. Thesrtiiicialkidueymsytake anyofvarimrsformsandneednotbedescrlbedhereindetail.l:lowever,thebasicoperationofthekdneyistoemploytheuseofa membrane l2 to eifectdiffusion of the waste-metabolites fromthebloodtbroughthekidneywithinchamber 14 into the dialysate chamber 16. It is to be understood thatappropriate conduits are connected from blood vessels of the animal toconduct-blood from the animal inmandoutof theariticiallddney l0. Itisalso to be understood thscappropriste conduits are to be employed toetlect conductance of the dialysate into. and out of kidney lil.-

The huid is moved through the artiileial ldduey lil'bymeans of n pump18. Pump 1B may take any of various conventional form such es 4u,centrifugal pump or thelike.lhetluid is then conducted from the pump 18into a heat transfer-apparatus 20;'Ihe apparatus 20 is to eEect removalof heat energy from the duid` thereby lowering the temperature of such.'Ihe cooler apparatus 2li-may takeany-of numerous various forms such asan appar-sms which operates similar-to the conventionalhomerefrigerator. It is believed to not be necessary `todescribeindetailtheoperatonofthecoolerzil.

-Theuld nowatthelowertemperatme,isthencoa ducted througharstvalve22intoaiirstsorbentchamber 24. The irstgsorbent chamber is to contain apacked bed of activated-carbon. Although the use of auch packed carbonbeds is conventional 'and need not be described here in detail, it isto'be understood ythat: the carbon bed employed within this invention isto be composed-of an amount of relatively grain-sized charcoal granules.It is also to be considered within the scope of this invention to employvthe cooler apparatus 20 in combination with the mmm ts soriseutmplished, the uid would bemaintsiued at a constant value oflowertemperature. The lower the temperature o! theuid passing throughthe chamber 24, the higher the absorption capacity of the charcoal.

The iluid is then conducted from thechamber 24 throughs. second valve 26intoa dow divider V28.v The ilo'w divider 2B is to permit selecting of aprimary tlow streamond asecondary ilow stream. Theprimary flowstrcamistobeconductedtl'uoughapolishstuhentchum-- beno toadditionallyremove more urea prior to the primary ow being vconducted back into the.artificial kidney l0. It is desired that the dialysate upon entering thekidney be extremely' close to the. temperature of blood. For thatpurpose, Au temperature adjuster 32 is to be employed in the dow path ofthe primary dow between the polish sorbent chamber 30 and the artiticalkidney l0. The structure-of thetemperauire adiusteris again conventionaiand may tion of the adjuster-*32 is to increase the temperature otparticularly to the drawing, there is shownV Atake any of various forms.The func- Y the dislyzing duid, ifuecesssry, to the blood temperamre ordecrease the temperature of the huid, if necessary. The

normal function ot the adjuster 32 will be to increase the lemperamre ofthe dialyzing duid. Also, a dialysate reservoir 3l is provided to supplyany dialysate vdcicfency ghichfntmoocm-m n? .as the desired rate of cw owing systn.

The secondary tlow 28 is conducter through a heat transfer apparatus 34.The apparatus 34 functions opposite to apparatus 20 in that apparatus 34Ysupplies heat energy into the diaiyzing fluid passing therethrough.Again, the apparatus 34 is deemedto be conventional and need not be.described here in detail. It may be desirable to connect together theappa.- ratuses 20 and 34 so thatthe heat energy removed within apparatus20 is-tben to he conducted back into the dialyziug duid throughapparatus 34. The dialyzing tluid Aleuving apparatus 34 is conductedthrough the second valve 26 into the second sorbent chamber 36. Asecondsorbent chamber isto also contain apacked 'bed of carbon aspreviously described. The carbon located within chambeu 36 is to havepreviously adsorbed urea at a much lower temperature. The dialyziugiluid is conducted from chamber l36 through the .lirst vulve 2z to aheat transfer apparatus 38. Apparatus `:ill is basically similar toappa-` talus 2O in that it ls'employed to eect the lowering of thetemperature of the dialynag iiuid. In eEect, apparatus .'ilthe beginningof a second stage of diaiysate concentra n.

The. duid is then transmitted intoa third sorbent chamber 40 through athird valve 42.`The sorbent chamber 40 is lo be `substantially similarto the sorbent chamber 24, that is, containing a bed of activated carbonwhich functions to remove urea and other waste metabolites from thedialyzing huid. The dialyzing fluid that leaves the sorbent chamber 40is then conducted through a fourth valve 44 to a flow divider 46. Thepdmary ilow stream from `the llow divider 46 is conducted hack to thediaiysate conduit located between `the pump liland the articial kidney10. Asa' result, this primary now stream is then permitted to reenterthe system vand again be conducted through cooler lo, iirst sorbentchamber 24, and so forth. The secondary low stream from the Alloverdivider 46 is conducted through a heat transfer apparatus 48 which isbasically similar to apparatus 34. As a result, the secondary flowstream of the fluid, which is raised in temperature, is passed from theheater 48 through the fourth valve 44 into thelourth sorbent chamber S0.Again, the sorbent chamber 59 is to be basically similar to sorbentchamber 36. The dialyzing iluid is then conducted from chamber 50through the valve 42 and than to be disposed of exterorly of the'system.

The operation o! Ithe regeneration system of this invention is asfollows: For illustrative purposes, the operation of ther'egeuerati'av'e system will be described iii-reference to the actualnumerical values which will 'be encountered in a typical situation.However. these numerical values can be conditions will actuallycharacteristics of the sorbent chambers as well as the ureaconcentration of the blood which will steadily diminish during thetreatment. The dlalysate will be-moved through the articial kidney 10 bymeans of the pump Il. It will be assumed that the urea concentrationwithin the dialyzingduid after exit from the kidney 10 is 50.0 mg.percent. Also, let it beassumed that a volume of BHO milliliters perminute of the dialyzing duid .is being moved by the let it be asumedthat'the cooler 20 is to lower the temperature ofthe dialy'zing duid toapproximately 30 C. and that temperature is to be maintained dzgringconducting ofV the iiuid through sorbent chamber veried and under-normal C. actiitis to be understood that vary depending upon thesorptiouv centration level of 3.8 is achieved. The flow divider 28 thendivides the dialyzing fluid into a primary ow of approximately 200milliliters per minute and a secondary flow of approximately 100milliliters per minute. Also, the urea concentration of the dialyzingfiuid after exit from chamber 24 has been decreased from 50 mg. percentto 2O mg. percent. The primary iiow from the ow divider 28 is thenconducted to a polish sorbent chamber 30 to remove an additional amountof urea. The dialyzing fluid from the chamber 30 is then increased intemperature by temperature adjuster 32 to approximately the value of theblood temperature. The primary flow is then transmitted from thetemperature adjuster back into chamber 16 of the artificial kidney 10.

The secondary ow from the ow divider 28 is elevated in temperature bymeans of heater 34 to approximately 60 C. This 100 milliliters perminute secondary flow stream, which is initially at 20 mg. percent ureaconcentration, is passed through sorbent chamber 36 through valve 26.Because the activated carbon within the chamber 36 contains a nearmaximum amount adsorbed of urea (for example, 3.8) again referring toFIG. 2. such carbon is capable of only adsorbing approximately a valueof 2.0 grams of urea per hundred grams of carbon. As a result, becausethe sorbent chamber 36 is fully loaded with urea at a previously lowertemperature, urea is acutally transferred from the carbon within chamber36 into the secondary stream of dialyzing fluid passing through chamber36. In essence, then, regeneration of the activated carbon withinchamber 36 occurs. The secondary stream of dialyzing uid is thenconducted from chamber 36 through valve 22.

The purpose of the valves 22 and 26 is to effect a switching of the flowpath between the chambers 24 and 36. Upon chamber 24 adsorbing near itsmaximum amount of urea and upon chamber 36 being regenerated a maximumamount (this ideally should occur simultaneouSly), valves 22 and 26 areactuated. As a result, the dialyzing fluid from pump 18 is then beingconducted Within chamber 36 with the secondary stream of fluid fromheater 34 being conducted to within chamber 24. Thereupon, chamber 24 isbeing regenerated while chamber 36 functions to adsorb urea. It is to benoted that now the cool dialyzing iiuid is being conducted withinchamber 36, thereby permitting the activated carbon within chamber 36 toadsorb a higher percentage of urea. It is also to be noted that theelevated temperature dialyzing uid of the secondary stream is beingconducted through chamber 24, thereby permitting chamber 24 to give upurea to the secondary stream of dialyzing fluid. This switched conditionexists until chamber 36 has adsorbed near the maximum amount of urea of3.8 with the chamber 24 being regenerated near the minimum value of 2.0.'I'he secondary stream of dialyzing uid contains a concentration ofapproximately 110 mg. percent of urea. This secondary flow stream isthen conducted to a second stage to effect further regeneration. Thesecondary stream of dialyzing fluid is conducted through a cooler 38through a valve 42 into a third sorbent chamber 40 which is basicallysimilar to chamber 24. The ow, after leaving chamber 40, is thenconducted through a valve 44 to a flow divider 46 which then causes thisow to be broken up into a primary stream and a secondary stream. Theprimary stream from flow divider 46 is then connected back into theconduit between the kidney and the pump 18. As a result, that portion ofthe dialysate is resupplied through the first stage through cooler 20and into chamber 24 and so forth. It is to be noted that the ureaconcentration after passing through chamber 40 is decreased from 110 mg.percent to approximately 50 mg. percent or less. It is desired that theconcentration of this primary stream be equal to or less than the ureaconcentration being conducted from the artificial kidney 10.

The secondary flow stream from the ow divider 46 is conducted through aheater 48, valve 44 and into a fourth sorbent chamber 50. Fourth sorbentchamber 50 is similar to chamber 36 in that it initially containsactivated carbon with a high concentration of urea. It is also to benoted that chamber 40 is to be at approximately 30 C. with chamber *50being approximately 60 C. It is also to be noted that of the mililitersper minute flow being conducted to Within flow divider 46, approximately67 mililiters per minute is being conducted by the primary stream backto the conduit adjacent pump I8. Only approximately 33 mililiters perminute of dialyzing fluid is being conducted through the sorbent chamber50. As a result of the secondary stream of iiuid passing through chamber50, the fluid has gained in urea concentration to approximately 200 mg.percent. This dialyzing solution, which is only about 10% of the amountof solution being passed through the artificial kidney 10, is then to bedisposed of.

It is possible that continued refinement of this to be disposed ofamount of fluid may be accomplished, if desired. If such refinementcontinues through a third stage regeneration system, only approximately3% of the dialyzing fluid would be lost, and the iiow rates through thevarious subsystems would be quite constant because water extracted fromthe body of' the patient would be approximately equivalent to the flowleaving the third stage.

lt is to be understood that appropriate metering devices wil be employedin combination with the regenerative system of this invention to informa person as to when to actuate valves 22, 26, 42 and 44. It is furtherbelieved to be within the scope of this invention to select various flowrates through flow dividers 28 and 46. It is also to be con` sideredwithin the scope of this invention to vary the temperaturecharacteristics of the heat transfer apparatuses, 20, 38, 34 and 48. Itis also to be considered a matter of choice or design as the particulartype of activated carbon bed to be employed within each sorbent chamber24, 36, 40 and 50. It is also to be considered a matter of choice ordesign as to the amount of activated carbon employed within each sorbentchamber.

As a result of employing the apparatus of this invention during a singletreatment in which 50 to 100 gallons of dialyzing `fluid is employedover a period of ten hours, only approximately five to ten gallons ofthat fluid wil be used. It is to be understood that the activated carbonwithin the sorbent chambers 24, 36, 40 and 50, as well as chamber 3l),will need periodic replacement with the non-regenerated chamber 30requiring most frequent replacement.

What is claimed is:

1. The method of regenerating the dialyzing fluid employed within anartificial kidney comprising the steps of lowering the temperature ofthe dialyzing uid leaving the artificial kidney to a predeterminedlevel;

causing the dialyzing uid to come into contact with a first inert solidsorbent to remove waste metabolites from the fluid;

dividing the main stream of fluid into a primary stream and a secondarystream, conducting the primary stream into the artificial kidney; and

raising the temperature of the secondary stream to a predeterminedlevel, causing the secondary stream to come into contact with a secondinert solid sorbent to remove waste metabolites from the sorbent.

2. The method as defined in claim 1 wherein:

lowering the temperature of the secondary stream after leaving thesecond inert solid sorbent;

a third inert solid sorbent to remove waste metabolites from the fluid;

olites from the fluid;

dividing the secondary stream into a first stream and a second stream;

conducting the first stream back through the first inert solid sorbent;and

7 raising the temperature of the second stream to a predetermined level,causing the second stream to come into contact with a fourth inert solidsorbent to remove waste metabolites from the sorbent. 3. The method asdefined in claim 2 which includes the addition step of:

disposing of the second stream.

4. The method as defined in claim 1 wherein:

selecting the volume of the secondary stream to be approximately thirtypercent of the primary stream.

5. The method as defined in claim 4 wherein:

selecting the volume of the second stream to be approximately thirtypercent of the first stream.

6. An apparatus for removing the waste metabolites from the dialyzingfluid of an artificial kidney comprising:

first means to lower the temperature of the main stream of dialyzingfluid being conducted from said artificial kidney;

second means to remove waste metabolites from said main stream aftercooling said second means includes a sorbent;

third means to divide said main stream into a primary stream and asecondary stream, said primary stream to supply uid into said artificialkidney;

fourth means to raise the temperature of said secondary stream; and

fifth means to transfer waste metabolites into said secondary stream,said fifth means include a sorbent.

7. The apparatus as defined in claim 6 wherein:

said second means includes a rst chamber of a packed inert solid, saidfifth means includes a second chamber of a packed inert solid; and

first valve means to selectively conduct said main stream of fiuid toeither said first chamber or said second chamber, said first valve meansalso selectively controlling said secondary stream of fluid from eithersaid first chamber or said second chamber.

8. The apparatus as defined in claim 7 wherein:

second valve means to selectively conduct said main stream from eithersaid first chamber or said second chamber to said third means, saidsecond valve means also selectively controlling said secondary stream offiuid from said third means into either said first chamber or saidsecond chamber.

9. The apparatus as defined in claim 8 wherein:

said first and second valve means being activated simultaneously.

10. The apparatus as defined in claim 9 wherein:

said inert solid located within said first and second chamberscomprising activated carbon.

11. The apparatus as defined in claim 9 wherein:

first passage means for directing the ow of said main stream throughsaid first chamber opposite to the direction of fiow of said secondarystream through said first chamber, second passage means for directingthe fiow of said main stream through said second chamber opposite to thedirection of fiow of said secondary stream through said second chamber.

12. Apparatus as defined in claim 6 wherein:

means for maintaining said secondary stream involume approximatelythirty percent of the volume of said primary stream.

13. Apparatus as defined in claim 12 wherein:

means for maintaining the difference in temperature between said mainstream and said secondary stream to be approximately thirty degreescentigrade.

14. Apparatus as defined in claim 6 wherein:

sixth means to lower the temperature of said secondary stream afterbeing conducted past said fifth means;

seventh means to remove waste metabolites from said secondary streamafter cooling, said seventh means includes a sorbent;

eighth means to divide said secondary stream into a first stream and asecond stream, said firstv stream being conducted to reenter said mainstream;

ninth means to raise the temperature of said second stream; and

tenth means to transfer waste metabolites into said second stream, saidtenth means includes -a sorbent.

15. Apparatus as defined in claim 14 wherein:

said sixth means includes a third chamber of a packed inert solid, saidtenth means includes a fourth chamber of a packed inert solid; and

third valve means to selectively conduct said secondary stream of iiuidto either said third chamber or said fourth chamber, said third valvemeans also selectively controlling said second stream of fluid fromeither said first chamber or said second chamber.

16. The apparatus as defined in claim 15 wherein:

a fourth valve means to selectively conduct said secondary stream offluid from either said third chamber or said fourth chamber to saideighth means,

said fourth valve means also selectively controlling said second streamof Huid from said eighth means into either said third chamber or saidfourth chamber.

17. The apparatus as defined in claim 16 wherein:

said third and fourth valve means being actuated simultaneously.

18. The apparatus as defined in claim 17 wherein:

said inert solid located within said third and fourth chamber comprisingactivated carbon.

19. The apparatus as defined in claim 17 wherein:

third passage means for directing the fiow of said secondary streamthrough said third chamber opposite to the direction of fiow of saidsecond stream through said third chamber, fourth passage means fordirecting the ow of said secondary stream through said fourth chamberopposite to the direction of fiow of said second stream through saidfourth chamber.

20. Apparatus as defined in claim 14 wherein:

means for maintaining said second stream in volume 30% of the volume ofsaid secondary stream.

2l. Apparatus as defined in claim 20 wherein:

means for maintaining the difference in temperature between saidsecondary stream and said second stream to be approximately 30 C.

22. Apparatus as defined in claim 14 wherein:

passage means to dispose said second stream after passing through saidtenth means.

References Cited UNITED STATES PATENTS 3,527,700 9/1970 Goldhaber 210-223,506,126 4/1970 Serfass et al 210-321 X 3,463,728 8/1969 Kolobow et al.210-22 2,963,519 12/1960 Kasperik et al. 210-34 X 2,978,407 4/1961Tuttle et a1 210--34 X REUBEN PRIEDMAN, Primary Examiner R. BARNES,Assistant Examiner U.S. Cl. X.R.

